1. Technical Field
The present invention relates to a semiconductor device containing a semiconductor element having characteristics changeable upon receipt of light.
2. Related Art
Semiconductor elements whose characteristics change upon receipt of light are, for example, a MOS transistor and a nonvolatile memory having a floating gate electrode. If these semiconductor elements receive incident light while packaging a bear chip or the like by a COG packaging method, in particular, the MOS transistor may change its on/off characteristics, and the nonvolatile memory may lose electrons injected into the floating gate electrode. In order to avoid these characteristic changes in the semiconductor elements, a light blocking layer to prevent irradiation of light is provided in the upper part of a region where these devices are provided.
One technique for blocking the light is disclosed in JP-A-2003-124363. In JP-A-2003-124363, a light-blocking region is provided surrounding a memory cell array effective region and its periphery and has a via layer and a contact layer provided at different levels. These via layer and contact layer are arranged in zigzag so as to suppress the light entering from lateral and diagonal directions.
However, even when the blocking region is provided surrounding the memory cell array effective region in order to reduce the light entering from the diagonal and lateral directions, there is a need, for example, to extend wires such as a signal line to outside the light-blocking region. Therefore, the via layer and the contact layer arranged in zigzag may not be able to completely surround the memory cell array effective region.